Autofluorescence-Guided Removal of Bacterial Biofilms from Wound Surfaces Using Cold Atmospheric Pressure Plasma

Abstract

Cold atmospheric pressure plasma (CAP) has shown potential to completely remove biofilms from surfaces [1] , [2] . The goal of this study is to employ the autofluorescence nature of bacterial biofilms to guide the removal of these biofilms from wounds using a CAP scalpel. Pseudomonas fluorescens biofilms which produce a green fluorescence under 405 nm UV light were grown on 12 chicken samples. The wound model (chicken tissue) is placed on a motorized X-Y stage with the plasma discharge device directly facing the sample. An image of the fluorescent biofilm region is captured using a Mightex BCN-B013-U monochrome camera and 560 nm green filter. The captured image then guides the X-Y stage to move such that only the fluorescent region is treated with CAP. CAP treatment of biofilm regions was carried out using a 1.37 lpm Ar/H 2 O plasma device with 39.5 x 54 mm dimension and a 1.5 mm tip. The discharge voltage and current are 3.24 kV and 1.2 mA respectively. The average speed of the plasma discharge over the substrate is 1 mm/s and the gap between the substrate and the discharge is 2 mm. To evaluate the action of CAP on the sample, before and after-fluorescent images were compared, CFU counts were taken, and 3D view of the effects were observed using a confocal microscope.